Automatic drain valve



Aug. 21,1945.

Filed May 27, 1943 as 111 111 115 l 114 g 101 74 64 57 fig. 2

n6 V x 122 126 146 1 INVENTOR 152151 155 145 121 CLYDE C'FARMER ATTORNEY brakesof the locomotive.

Patented Aug. 21, 1945 r p nuromrronnmvmlvs "Clyde drawer, Pittsburgh, massa re Th p p Westinghouse Air Brake Conipanmwilmerding',

2a., a corporation of Pennsylvania Application May 27,mastermind488,670]

solarms. (oreos- -ssj This invention relates to compressed air systemsgand more.particularly to automaticidrain valve means i operative to discharge condensate accumulating in the storage reservoir of man brake system. I q

r I Various designs of inexpensive drain: valves have-been proposed for efiecting intermittent discharge of condensed moisture from air storage reservoirs, such as the main reservoir :forming part of an air brake equipment on a locomotive, where accumulation of water from the compressed air constitutes a well known source of operating difliculties. Although certain types of drain valve devices have .proven satisfactory while new and operating under favorable service conditions, excessive loss of airranddother difficulties may be experienced after wearing of parts has become advanced. Thus there still remains a need for a. sturdy and reliable dram valve apparatus constructed andarrahgied to discharge condensate from areservoir during measured. intervalsautomatically timed in accordance, with a recurring operating condition, such as application of the brakes. i 1 :It is a principal object of mylinvention to proratus act the class abovedescrihed comprising condensatedischarge valve means so constructed and. arranged. as to reduce toa minimum the leakage of air. while the drain valveapparatus vide an. improved automatic drain valve appais inoperative, and fluid pressure timing means for automaticallyregulating the interval during which the discharge communication remains Another object of the invention is to provide an improved drain valve devicehaving the characteristics just mentioned and adapted to operate'in response to each applicationof the l The advantages and novel features of the in vention will be better understood upon consideration ofthe following detailed description taken in connection with the accompanying drawing, wherein l Fig.1 is "adiagraminatic sectional viewi'ot an automatic drain valve device constructed in accordance with one form of theinventioni 3 Fig. 2 is a diagrammaticsectional view of a drain valve device embodying the invention in a different form; and l a if Fig.3 is a similar view of a drain valve apparatus, mainly in section, exhibiting the features of a third species of the invention. it

A a nis in. Figure 1 @The equipmentashown in- Fig. 1 includes a main reservoir 5,, which is .ofbtheutype usually carried on a locomotive and. supplied with compressed air by a compressor (not shown) a: brake cylinder 6, and an automatic drain valve device flwazranged to collect andsdischarge condensate from the reservoir in response to the pressureiof air supplied to the brake cylinden; i

The drain valve device 1 comprises a pipe bracket wthaving boltedvor otherwise secured thereto a casing section" It inwwhich is formed a valve chamber 12 communicating with an atmospheric port 135 Mounted in the valve chamher his a slide valve I5 .whichlis yieldingly held On a seat It under the force of a spring .I! that is. interposed between anupper wall of the valve chamherandsacollar carriedbyrastrut l8. For, i

operating the slide a valve there i is provided a lever 2ll hav'ing one end pivotally connected to the valve and the other end journaledt ona pin 24 carriedby the casing structureyand operatively connected by an intermediate pin- 22 toa follower member 23, oneend of which isLslidably mounted in a bore 24 formed in a cap member 25 secured to the casing lll' The other end of the follower member--23 isfsecured to a flexible diaphragm 21 which is interposed between" the casing section 41 anda cover section28, and

which issubiect-to the opposing forces of fluid pressure in a chamber formed at the outer face of thediaphraghr and thepressureof a spring- 3| interposed between follower -23 and.

the cap 'me'mber 25; The diaphragm chamber 30 commumc-ates by way of a {passage and pipe i whe s-he air brakes arereleased andthebrake cylinder pipe is -vented to the atmosphere the 'us'uai'manner, the-spring '3! is effective to hold the follower member flii, diaphragm. 21*and slidewalve-" lfi in the normal position-in which these elements are shown in Fig. 1. Condensed moisture" is at this time freeto flowiromthe reservoir 5 intoa drain chamber 38 formed {in-a casinlg section Bdcarried by} casing section H byway or a'pipe 40,- a passage 41, a cavity '42.

in the slide valve; and-a passage and tube 43 at the bottom of the} drain chamber. At thesame time; a second cavity lfi in the slide valve is positioned for connecting the vented -brake cylinder passage 34 to ei-passage 41 communicating with a timing chamber 48, which is formed inthe casingsection H;

' Whenan application of the brakes iseficcted compressed air is supplied in the usual manner through'the brake cylinder pipetfi to the brake eyl'mder'fi, and also flows by wayof the pipe and passage 34 to'the] diaphragm chamber 30, and

byway of cavity 46 and passage 4 to the volume chamber 48. The volume chamber 48 is thereby charged with air under pressure until theiiuid pressure acting on the diaphragm 21 isincreased to the predetennined value required-for overcoming the opposing force :of spring 31,. whereupon th diaphragm, follower. member 123', and

while communication is established between that chamber and drain chamber 38 by way of pas-" sage 41, cavity 46, and a passage 5|. 'Atthe same time the passage 43 is connected through the cavity 42 with an atmospheric ,discharg'e 'passage;

53, with the result that the water previouslylde 65, diaphragms 64 and 63, and slide valve 13 in their normal positions, as shown in the drawing. With vthe slide valve 13 in the normal position, a" drain communication is maintained between thelowermost portion or sump f the main res- -ervoir a and the drain chamber 85 in the drain "valve device, by way of a pipe and passage 88, a

cavity..89. in the slide valve, and passage 86, so that condensate accumulated in the reservoir is free to flow into'the drain chamber. It will be T understood that since the intermediate chamber posited in the drain chamber 38 is arivenout through the tube and passage. 43, cavity 42 and 1.

discharge passage 53, under the pressure of .air. with which both chambers 38 and 48 have been charged, Compressed air is prevented from escaping from the main reservoir 5. at this time, since the slide valve.v l5, has been positioned to close the passage 4|. When the brakes are released, compressedair is :vented from the brake cylinder 6 and dia.* phragm. chamber 38 by way of thepipe 35, and other communications establishedby the usual brake controlling valve. The spring 3| is then rendered effective to return the follower member 23 and slide valve |5.to the positions in which they are shown inrFig. 1. The slide Valve is thus operated to reestablish the drain communications hereinbefore described and through which 0011-. densate is forced from the main reservoir. into the drain chamber 38 in the automaticdrain valve device, andthe apparatus is then conditioned for another cycle of operation.

Ap aratus m Fig. 2

Illustrated in Fig. 2 is a modified form of automatic drain valve device 51 having a casing structur made up of casing sections 58, 59 and 68, which maybe bolted or otherwise secured together by suitablemeans, not shown. Clamped between the casing section 59 and the respective sections 58 and 68. are a pair of similar flexible diaphragms 63 and 64, which areconnected to gether through the medium of a follower member Y65 and urgedupwardly,,withdiaphragm 63 engaging a stop boss 66 as shown in the drawing, under the force exerted by a coil spring 61 that is interposed between the follower member and a partition 68 formed in the casing section 68. Between the diaphragins is a valve chamber 18 communicating by way of a pipe 1| with the reservoir 5a, and which has mounted therein a slide valve 13 that is held on a valve seat fl I through the medium of a spring 15. and a strut member 16. The strut member 16 is journaled on apin 11 carried by the casing section 59, and is pivotally connected-by means of a-pin 19 to the follower member 65, which-is thus adapted to actuate slide valve 13 through the medium of the strut member. v

At the upper side of the diaphragm 63 is formed a chamber 88 which communicates by way of a pipe 8| with the brake cylinder 60. Formed. within the casing section 68 is a chamber83which is disposed intermediate the diaphragm 64 and the partition .68 and is connected to the atmos- 18 is connected with the main reservoir 5a, the reservoirpressure is equally distributed in opposing directions over the two diaphragms 63 and 64, and is thus not effective to control thepositioning thereof. The reservoir pressure inchamber 18 is, however, effective to maintain the slide .65 arethen moved downwardly. until .a follower plate 65a at the lower facev of diaphrgam is brought into engagement with the partition 68. In so moving, the follower member 65 operates the strut 16 throughthe .medium of the "pin 19 for moving the slide valve 13 to a new position, wherein communication between the.reservoir pipe .88 and passage 86 is cutoff, while the passage is connected to a discharge port 98. Air previously stored up at main. reservoir pressure in drain chamber85 thereupondrives out the condensate by way of the passage 86, slide valve cavity 89, and discharge port 98.

Upon release of the compressed air from'the brake cylinder and consequently from the diaphragm chamber 88 of the drain valve device, the spring61 is rendered effective to shift the diaphragm assembly andv the slide valve 13 into the normal position in which these elements are shownin Fig. 2, thereby reestablishing the original communications already described. r

Apparatus in Figure Illustrated in 3 is an automatic drain valve device embodying features of the invention in a form enabling the mounting of the device in phere through a port 84. A drain chamber 85 is closeassociationwiththe main reservoir inlet connection, so that the possibilityof freezing of the parts will be minimized due to conduction thereto of heat of compression from the air being sup-plied toq the reservoir from the usual compressor. The apparatus shown in Fig.3 includesan air compressor indicated generally by the reference character I88, which is operative to supply compressed .air to a main reservoir 5b by way of a compressor discharge pipe |8|, a drain valve device I82, and the usual brake cylinder 62). The casing structure :of thevdrain valve device I 02 ,includes a casing section I and a pipe bracket I86, the latter; of which has integrally formed thereon an extension which constitutes a pipe union portion 188; forming part of the air-conduit assembly;connecting the compressor I88 to the main reservoir 5b. The pipe union portion 88 has'a suitable flange adapted to be secured toan end wall N8 of the main reservoir by means of bolts 1 The pipe union assembly is completed bya clamping ring 3 and an annular nut ||4 which are adapted to be secured to the portion 188' the II adjacent end of compressor discharge pipe IIII.

Formed in the casing section I is a valve chamber I I6 which is adapted to receive condensate from the, main reservoir 5b by way of apassage II8 formed in casing section I05 and pipe bracket I06, and a syphon tube I ISIhaving its upper end suitably connected to the reservoir end wall IIO and its lower end opening adjacent the bottom of the reservoir. Mounted within the chamber I I5 is a follower member I20, which is operatively connected to a slide valve I2I,I

and has an annular seat rib I22 that isadapted I member is maintained in a normal position under the force of a coil spring I24, as shown in I the drawing. The spring I24 is interposed between a hollow plunger I25 abutting follower member I20, and a capmember carried by the end of the casing section I05. The slide valve I I 2III is operative to control communication between the valve chamber IIS and a drain pas- I drainIvalve device I02 is thus operative in response to an increase in brake cylinder pressure I to permit discharge of condensate from the main reservoir for a limited interval of time, the cycle I of operation ofthe slide valve element from its I closed position to its opened position and then back to the closed position being completed independently of the pressure of air maintained in I the brake cylinder.

to be held in engagement witha gasketI23 carried by the casing section, when the follower I I. From the foregoing description of three structurally different drain valve devices'embodying my invention, there are thus exhibited some of the advantages obtainable by the association ,with

I a compressed air storage reservoir of a drain valve assembly including a loaded slide valve controlling a drainage outlet, and fiuidpressure responsage I26, as hereinafter I explained. A 0011 II spring I21 is preferablyinterposed betweenItheI follower member I and the slide valve for proper engagement I maintaining the latter in with its seat. I I I For actuating the slide valve assembly there is provided a piston I30, which is slidablye mounted Iin a suitable bore in the casing section I drain passage and a discharge port, a spring, a movable abutment subject to theopposing pres-I I05, forming on one side thereof a pressure I chamber I3I which communicates through a passage and pipe I32 with the brake cylinder. 6b. At the opposite side of the piston I is" I formed a chamber I33 opening into a timing chamber I 35, [which communicates by way of a restricted passage I36 with passage I32. I An annular seat rib B8 is formed on thep iston I30 within chamber I33 and in operative alignment with a gasket I39, which is disposed adjacent a bore in the casing section through which extends a piston stem I that engages the fol- I; lower member I20.

In operation, compressed air supplied to the brake cylinder 61), in efi'ecting an application of the brakes, flows through the pipe and passage I32 to the piston chamber I3I, and 'moves the piston I30, follower member I20 and slide valve I2I to the right, as viewed in Fig. 3, overcoming the force exerted by the coil spring I24 against plunger I25. With the slide valve I2I in'thisI position, a cavity 145 therein connects a passage I with the drain passage I26, with: the

: result that condensate accumulated in the main reservoir 5?) is driven out by wayI of the syphon tube H9, passage H8 in the drain valve device, 1

valve chamber H6, and the'said communication I46, I45 and I26. I I

It will be understood, however, that the slide valve I2I is maintained in the discharge position I a brake cylinder in an airbrake equipment, of a. I

I sures of air in the brake cylinder and of said spring, and a slide valve actuated by said movable abutment and operative to establish communication between 'said drain passage and said discharge port, said slide valve being constructed I and arranged to be constantly loaded under the pressure of air insaid reservoir. I

2.I.The-combination with a main reservoir and drain valve device comprising a casing having a piston chamber communicating withsaid brake cylinder and a timing chamber also communicating therewith, by way of a restricted port, a slide valve mounted in said casing for controlling a drainage communication through which conden-I sate can be discharged from said main reservoir, I said slide valve being constantly loaded under the pressure of air in said reservoir, a spring for normallypositioning said; slide valve means to close said drainage communication, and a piston subjectto the opposing pressures of fluid in said piston chamberand of fiuidin said timing chamber,

said piston being responsive to an increase in I brake cylinder pressure for operating said valve only for the interval of time required for the I build up of fluid pressure in the timing chamber I35 an chamber I 33 by flow of compressed air through the restricted passage I30. As this fluid pressure approaches that of the air in piston I chamber I 3|, the spring I24 is rendered effective to move the plunger I25, follower member I20,

slide valve I2I, and piston I30 back to the normal I positions in which these members are shown in Fig. 3. The reservoir drainage communication is thus cut off inItimeto prevent undesired waste of compressed air from the main reservoir. The

means to open said drainage communication for a limited time. I I I I 3. The combination with a drain valve apparatus including a casing structure carried by the main reservoir and having a drainage communication, a syphon tube mounted within said reservoir and having one end opening adjacent the bottom wall thereof and the other end connected to said discharge communication, a slide valve mounted in said casing for normally closing said drainage communication, said slide valve being constantly loaded under the pressure I of air in said reservoir, and movable abutment means constructed and arranged to respond team I increase in brake cylinder pressure for operating said valve to open said drainage communication for a predetermined interval. I. I

I I i CLYDE C,FAR1\IIER.

only a small quantity of I main reservoir and I I a brake cylinder in an air brake equipment, of a 

